It's not ok. I can see the interest in it from a marketeers point of view being that you can target localised marketing to people so rather than a company that

It's not ok. I can see the interest in it from a marketeers point of view being that you can target localised marketing to people so rather than a company thats 30 miles way you might see adverts for companies within walking distance. However on the flip side to that I think it's quite useless as realtime marketing because if someone is out looking for a post office, or somewhere to eat they are more likely to open their maps app and search or look around using their eyes and it's reasonable for the maps app to show location based information because thats what it does. Then we get to having data of where someone has been (non-realtime) which has similar benefits to marketeers but also poses the same serious privacy issues. I don't personally believe location data should be broadcast outside of the device without the users explicit knowledge of where it's going and why its being sent, e.g find my phone functionality, mapping apps, share location with a friend your meeting.